Many industrial and environmental processes involve turbulent dispersed two-phase flows, such as gaseous flows laden with solid particles or liquid drops and liquids containing solid particles or bubbles. In such flows, discrete particles, i.e., drops or bubbles constitute a disperse phase, whereas the carrier liquid or gas represents a continuum or continuous phase. The disperse phase can move somewhat differently from the continuous phase and the motion of both phases can be complicated. Examples include the combustion of coal, tobacco and other plant material.
Tobacco smoke is a complex and dynamic matrix consisting of more than 4800 compounds. It is composed of a gas phase and a particulate phase and many semi-volatile substances are partitioned between these two phases. The majority of substances can be found in the particulate phase. Even so, the gas phase consists of 400 to 500 individual compounds of which about 300 can be classified as semi-volatiles. Most of these smoke constituents are at trace levels (less than 100 parts per million). The chemical composition and partition between both phases can change continuously and is strongly influenced by time, temperature, chemistry and dilution of the tobacco smoke in the matrix. More recently, electronic cigarettes, e-cigarettes, have grown in popularity. These e-cigarettes utilize solutions containing both a variety of chemicals found in tobacco as well as low vapor pressure polymers that are used to produce the smoke phenomena. This combination of materials presents a challenge to the laboratory employing classical analytical methods and makes the development of new methods for determination of the composition of the solution for molecules that are present pre- and post-vaporization critical.
Similarly, the development of medical marijuana and its commercialization has led to the need for improved methods for drug and drug metabolite isolation and detection when they are present in body fluids including urine and oral fluid. As commercial oral fluid sampling devices utilize surfactants and polymers to disrupt microbiological activity and stabilize those samples for future analysis, being able to eliminate or separate surfactants and/or polymers from the sample presents a challenge that classically trained analytical chemist will need tools to address.